1. Technical Field
The present invention relates to a charging apparatus using a pad type electrode contact point.
2. Description of the Related Art
Due to the wide spreading of a portable phone in accordance with the development of a wireless communication technology, a ubiquitous information environment for everybody to transmit and receive desired information anytime and anywhere has been created.
However, up to now, communication terminal devices have depended on a battery, and terminals having battery of which power is rapidly consumed according to a use degree, such as a smart phone, have a limitation in which they should be recharged after being used for several hours.
Further, a jack of a charging adaptor should be intentionally connected to a wireless terminal in order to charge the wireless terminal, and a call can not but be made in a state in which a power line is connected to the wireless terminal during the charging of the wireless terminal.
In order to solve a problem such as a limitation of movement of a user of the wireless terminal due to the connection of the jack of the charging adaptor as described above, or the like, to provide convenience to the user, technologies of transmitting power using a magnetic coupling scheme based on Faraday's law have been developed.
An example of these technologies includes a magnetic resonant technology by energy conversion between a magnetic field and an electric field, a magnetic induction technology using magnetic coupling according to a transformer principle, and the like.
These two technologies, which are technologies by a magnetic coupling scheme, may be different in view of a coupling energy mechanism from each other. However, they may be similar to each other in that they uses an energy action between a transmit side primary coil and a receive side secondary coil.
In connection with this, in the magnetic resonance technology, energy is concentrated on a specific resonance frequency by a resonator configured of a coil type inductor L ad a capacitor C and is transmitted to a receive side in a magnetic energy form, and an LC resonator having the same resonance frequency as the specific resonance frequency receives the transmitted energy while showing a tuning phenomenon.
This scheme has an advantage in that relatively large energy may be transmitted up to several meters (m). However, since a transmission distance depends on a size of a coil, the size of the coil should be increased by an increased distance.
In addition, impedance mismatching is generated according to a distance between transmit and receive resonators to deteriorate efficiency. Therefore, an automatic impedance circuit is required.
Meanwhile, the magnetic induction technology uses relatively high power and has more excellent efficiency as compared to the magnetic resonance technology, such that it has been mainly used in manufacturing a charging pad type product. However, the magnetic induction technology has large disadvantages such as a rapid change in efficiency according to coil alignment and heat generation of a metal.
In addition, a pad type charger to which the magnetic induction scheme is similar to an electrode contact point scheme since an electrode is not exposed to the outside and a degree of freedom for a distance is not large.
Most of all, in the technologies of the magnetic coupling scheme, a series of processes of converting direct current (DC) power of an adaptor into alternate current (AC) power using a converter and transmitting the AC power to a receive side using a coil, at a transmit side, and converting the AC power into DC power through a rectifier should be performed. Due to these conversion processes, circuits may become complicated, efficiency may be decreased, and a manufacturing cost may be increased. In addition, since a high power magnetic field is used, sensitivity of a communication device such as a portable phone may be deteriorated.